The present disclosure relates to a sheet stacking tray which is mounted on an image forming apparatus such as copiers and printers and on which sheets to be discharged are stacked, the disclosure further relating to a sheet postprocessing device, as well as an image forming apparatus, including the sheet stacking tray.
Image forming apparatuses such as copiers and laser printers are equipped with a sheet (paper) discharge tray in order to discharge a sheet on which a desired image has been formed by electrophotographic process or to discharge a document which has been conveyed up to a document reading part by a document conveyance unit and subjected to a reading process of a document image.
For such a sheet discharge tray, it has conventionally been the case that a noren-like sheet presser member (a noren is a Japanese shop-front curtain partly slit for easier entrance) is placed at a sheet discharge opening to suppress curling of a discharged sheet which could occur to widthwise both-end portions of the sheet. Then, unfortunately, the discharged sheet may be directed downward by the sheet presser member, so that a forward end portion of the sheet may come into contact with a top surface of the sheet discharge tray as the forward end portion of the sheet is in a generally vertically erect state or is curled toward a wall surface provided on the upstream side in the discharge direction. When the sheet is further discharged up to its rear end portion in this state, there would be a fear that the sheet is discharged with its upside down or in a rounded state.
This being the case, there has been known a method, for example, in which a member for imparting stiffness to the sheet by making contact therewith is provided at a sheet discharge opening so as to suppress rounding or inversion of the sheet.